Question

State one observation for the following:

(ii) Sodium hydroxide solution is added to ferric chloride solution at first a little and then in excess.

Answer 1

When iron (III) chloride $\left({\mathrm{FeCl}}_3\right)$ reacts with sodium hydroxide $\left(\mathrm{NaOH}\right)$, the formation of a reddish brown colored precipitate of ferric hydroxide $\left(\mathrm{Fe}{\left(\mathrm{OH}\right)}_3\right)$ takes place.

• The reaction can be represented as:

$$\begin{gathered} {\mathrm{FeCl}}_3\left(\mathrm{aq}\right)+3\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{Fe}{\left(\mathrm{OH}\right)}_3\downarrow +3\mathrm{NaCl}\left(\mathrm{aq}\right) \\ \mathrm{Reddish}\mathrm{brown} \end{gathered}$$

This precipitate is insoluble in excess of sodium hydroxide solution.